The present invention relates to a lock arrangement for a transmission, in particular a parking-lock arrangement for an automated transmission, the lock arrangement being prestressed by a first spring accumulator into a locking position in which the transmission is locked, and the lock arrangement being capable of being shifted by means of an actuator from the locking position into a release position in which the transmission is unlocked.
Parking-lock arrangements of this type are known for automatic transmissions, including automatic converters, automated shift transmissions, double clutch transmissions, etc.
The present invention relates, furthermore, to a method for activating such a lock arrangement.
DE 41 27 991 C2 discloses a parking lock for an automatic transmission, with a spring accumulator which generally presses the parking lock into the locking position, and with an electrohydraulic actuator, by means of which the parking lock can be pressed into the release position. To hold the release position, a pressure-medium accumulator may be provided. In a modification, a mechanical bistable flip-flop is provided, which retains the parking lock mechanically in both positions. Pressure medium is then necessary only for changes in the positions. A position sensor detects the position of the parking lock.
DE 10 2004 021 981 A1 shows a parking lock with a spring accumulator for setting the locking position and with a release device for setting the release position. An electromagnetic holding device holds the parking lock in the release position. The release device can be actuated by means of a transmission actuator.
A parking lock with a holding device for holding the parking lock in the release position is also known from DE 198 34 156 A1, DE 102 12 038 A1 and DE 100 37 565 A1. By the electronic actuation of the holding device, the holding device is released and the parking lock is transferred into the locking position by means of a spring accumulator. In this case, there may be provision for monitoring the position by means of a sensor.
DE 198 34 156 A1 and DE 100 37 565 A1 in this case show solutions for transferring the parking lock into the locking position by means of a fluid actuator. For this purpose, the parking lock of DE 102 12 038 A1 uses an electric motor.
Furthermore, DE 198 04 640 A1 also shows a parking lock, in which the position is checked electronically. If a fault is detected, an actuator-actuable parking brake is actuated.